Just missing that allowed iOS Maps application select it as default, and in fact it is now possible, but only if you have a jailbroken iPhone. The modification must install MapsOpener called.

MapsOpener turns Google Maps into the maps application "native", any link you click will now open in Google Maps instead of the Apple Maps. Works also with addresses, if they send you email address and pressing opens Google's app. This happens when we talk about iOS 6, where the Maps application is different from Google that we had in iOS 5, but many users are still todavían enjoying your iOS 5 untethered jailbreak, what happens in this case? Same thing, the Google application, the non-native, becomes the default application. And if you have iOS 5 I recommend installing the new application and this tweak and forget about the old, the new has turn by turn navigation and and some new maps that consume less data than the previous version, the native. If you have iOS 6 and have to choose, I personally do not dislike the Apple Maps application, but I recognize that the implementation of Google has more things, better satellite maps, Street View, etc..

You can download for free from Cydia, you'll find it in the BigBoss repo. You need to have done the jailbreak on your device.